-->
Page 1 of 1

shiftOut and shiftIn without delay - is this good?

PostPosted: Thu Aug 25, 2016 1:30 pm
by Thomas S.
I just looked into core_esp8266_wiring_shift.c vs wiring_shift.c

To my astonishment I saw no delays in the esp8266 version. As it runs 5 times as fast as a 16 MHz arduino, I wonder if it is ok to assume, that connected hardware can cope with this speed.

Or is the digitalWrite() function by itself slowed down for the esp?

HX711 : max 2.5 MHz on clock pin

PostPosted: Thu Aug 25, 2016 1:48 pm
by Thomas S.
I just checked the datasheet for the HX711. It gives a minimum for PD_SCK high time of 0.2 us, and a minimum for PD_SCK low time of 0.2 us, so it should not be working.

I don't know, how many clock cycles it takes to call digitalWrite(), but I asume it is not more than 4 cycles, plus maybe 2 for the loop, so the esp runs with 10 Mhz on the clock pin?